In the summer of 1994, in the tallest of Princeton University's ivory towers, Andrew Wiles was completing one of the most extraordinary odysseys in the history of math. For more than three decades, Wiles had been obsessed with Fermat's Last Theorem, a seemingly simple problem that had stumped mathematicians for 350 years. French mathematician Pierre de Fermat had noted that although there are plenty of solutions to the equation X2 + Y2 = Z2 (for example, 32 + 42 = 52), there is no corresponding solution if the numbers are cubed instead of squared. In fact, Fermat scribbled in the margin of a book that he had "truly marvelous" proof that the equation Xn + Yn = Zn has no solution if n is any number greater than 2. Unfortunately, he never put his proof on paper.

Wiles was 10 years old when he encountered the theorem. "It looked so simple, and yet all the great mathematicians in history couldn't solve it. I knew from that moment that I had to." When classmates were flocking to rock concerts, he was studying how geniuses of prior eras approached the problem. He abandoned the quest after college in order to focus on his budding academic career, but his obsession was rekindled in 1986, when a fellow mathematician showed that proving a certain mathematical hypothesis—this one unsolved for a mere 30 years—would also prove Fermat's theorem. He set aside all but the few classes he was teaching—and revealed his quest to no one but his wife. To disguise his single-mindedness, he rationed the publication of previously completed work.

Despite long hours of focus—his only source of relaxation was playing with his two young children—the next few years produced little concrete progress. "I wasn't going to give up. It was just a question of which method would work," says Wiles. In 1993, after seven straight years of intense work—more than 15,000 hours—Wiles stepped up to the podium at a conference in England and, over the course of three lectures, presented his completed proof of Fermat's Last Theorem.

A media frenzy followed. The shy mathematician found himself named one of People magazine's 25 Most Intriguing People of the Year, alongside Oprah and Princess Diana. But a handful of peer reviewers poring over the 200-page proof found several small errors. Wiles set to work addressing them. After a full year of frustrating struggle, Wiles had the insight that allowed him to fix them.

Wiles' intellect is inarguably impressive; one of his colleagues told The New York Times that only 1 in 1,000 professional mathematicians were capable of understanding Wiles' work. However, the Princeton professor himself attributes his accomplishment not to his brains but to his persistence. "For me, it was the main thing," he says.

It is likely that somewhere, at this very moment, a parent or coach is declaring to a discouraged child that "quitters never win." But perseverance has come to seem like quaint lip service against the tide of interest in talent and aptitude, flashier gifts that nature, or genes, seem to inarguably confer.

And yet grit may turn out to be at least as good a gauge of future success as talent itself. In a series of provocative new studies at the University of Pennsylvania, researchers find that the gritty are more likely to achieve success in school, work and other pursuits—perhaps because their passion and commitment help them endure the inevitable setbacks that occur in any long-term undertaking. In other words, it's not just talent that matters but also character. "Unless you're a genius, I don't think that you can ever do better than your competitors without a quality like grit," says Martin E. P. Seligman, director of the university's Positive Psychology Center.

Indeed, experts often speak of the "10-year rule"—that it takes at least a decade of hard work or practice to become highly successful in most endeavors, from managing a hardware store to writing sitcoms—and the ability to persist in the face of obstacles is almost always an essential ingredient in major achievements. The good news: Perhaps even more than talent, grit can be cultivated and strengthened.

How Much Does Talent Count?

Many of life's failures are people who did not realize how close they were to success when they gave up," opined Thomas Edison, a man almost as famous for lauding perspiration as he is for inventing the lightbulb. If effort is the bedrock of success, what role do intelligence and other abilities play? "IQ counts for different amounts depending on the task and situation," emphasizes intelligence expert Robert Sternberg, dean of arts and sciences at Tufts University.

Many large-scale analyses, however, suggest that a mere 25 percent of the differences between individuals in job performance—and a third of the difference in grade point average—can be attributed to IQ (personality factors, creativity and luck are said to contribute to the other 75 percent). Angela Duckworth, a graduate student at Penn who, together with Seligman, has conducted several key studies on grit, argues that the precise number isn't as important as knowing that intelligence accounts for only a fraction of success.

If 25 percent seems surprisingly low, that's partly because the hard work and determination that go into accomplishing Something Important are overshadowed by those rare but delightful lightning strikes of inspiration, mythologized as the visit of the Muse. "Unfortunately, no one comes in my window and whispers poems to me," laments David Baker, director of creative writing at Denison University and author of seven books of poetry, including Midwest Eclogue. "Poets work hard. I may work on a single poem for weeks or months and write 60 or 70 drafts—only to decide that draft 22 was the good one."

Such persistence is vital even for an indisputable genius. Mozart's diaries, for example, contain an oft-cited passage in which the composer reports that an entire symphony appeared, supposedly intact, in his head. "But no one ever quotes the next paragraph, where he talks about how he refined the work for months," notes Jonathan Plucker, an educational psychologist at Indiana University.

Angela Duckworth had studied neurobiology in college and eventually went on to teach, including a stint at a school for low-income children. "It became pretty obvious to me that IQ didn't explain why so many of the kids had reading skills that were four grade levels below their average," she says. "The failure of kids to reach their potential was almost hitting me over the head." Already in her 30s and with a young child, Duckworth was intrigued enough to return to school for a Ph.D.

She approached Seligman, best known for his groundbreaking work on optimism, and together, they began identifying high achievers in various fields, interviewing them and describing the characteristics that distinguished them.

"There were certainly a fair number of people who were brilliant, ambitious and persevering," Duckworth reports. "But there were also a lot who were not a genius in any way but were really tenacious." They began referring to this tenacity as grit—the determination to accomplish an ambitious, long-term goal despite the inevitable obstacles. Grit clearly resides in the same psychological neighborhood as motivation and self-discipline, but it's on a distinct property—and no one had ever knocked on its front door before.

Altogether Different

Not that researchers have ignored it altogether. Louis Terman, the legendary psychologist who followed a group of gifted boys from childhood to middle age, reported that "persistence in the accomplishment of ends" was one of the factors that distinguished the most successful men from the least successful. And in the most-cited paper in the giftedness literature, University of Connecticut psychologist Joseph Renzulli, director of the National Research Center on the Gifted and Talented, argued that "task commitment"—perseverance, endurance and hard work—is one of the three essential components of giftedness (along with ability and creativity). Indeed, Renzulli says, the evidence that these nonintellectual factors are critical to giftedness is "nothing short of overwhelming."

For the 95 percent of humanity that isn't recognized as gifted, Duckworth and Seligman have an egalitarian finding: Grit has value for people at all levels of ability.

In fact, their initial studies show that grit and intelligence are completely independent traits. Both enhance the likelihood of success, but the brightest among us are no more likely than the dimmest to be gritty. "I would be surprised if grit only matters for the upper echelons," Duckworth says. "One could argue that if you don't have a lot of raw ability, it's doubly important to be focused, hardworking and able to bounce back from setbacks."

The Penn researchers have already found that grit is valuable in a variety of real-world academic settings—such as middle school spelling bees. And they're looking at its real-world value among real estate agents and Wharton Business School grads.

They've proved that grit is the premier attribute for surviving the grueling first summer of training at West Point ("Beast Barracks"), when as many as 5 percent of new cadets typically drop out. "West Point costs hundreds of thousands of dollars per student, so the military has a keen interest in predicting attrition," Duckworth explains. A grit questionnaire administered to all 1,223 cadets entering the class of 2008 showed that grit is the single best yardstick for predicting who will survive the academy's punishing first weeks. It bested such highly touted measures as high school class rank, SAT scores, athletic experience and faculty appraisal scores. "Sticking with West Point doesn't have as much to do with how smart you are as your character does," Duckworth concludes.

The Power of Passion

Certainly character was a tremendous asset to Andrew Wiles, who says he has a "single-mindedness that I don't see in most other people." But he also had "a special passion" for Fermat's Last Theorem. It is this sort of fervor and fascination that might just be the cornerstone of grit.

The idea that passion fuels perseverance has crucial implications: If grit—and hence high achievement—hinges on passion, then it's especially important for parents to expose their children to the broadest possible range of academic, artistic and athletic activities, to maximize the chances that something will capture the child's imagination. Helping children find their passion may turn out to be more important than addressing their academic weaknesses.

Renzulli points to his own son as Exhibit A. From early childhood, the boy was, in his father's words, "an electrical, mechanical and scientific genius." He routinely received As in science and math—but Cs in English and history. "He would bring home his report card and his mother would go ballistic," Renzulli recalls. But convinced that his son's love of science was the key to his future success, Renzulli wasn't concerned. "I'd take him for a car ride, get some ice cream and say, 'I'm as happy as a lark that you are doing what you're doing. And I don't care about those Cs.'" The younger Renzulli, now in his 30s, has become a highly successful researcher.

Although extremely persistent people are usually passionate about their work, that doesn't mean that the passion always comes first. Perseverance, notes Duckworth, can itself foster passion. Often the most fascinating aspects of a topic (particularly a highly complex one) become apparent only after deep immersion, to a level "where you understand it and are enlivened by it."

Such is the case with Duckworth herself, who says that she decided on graduate school after a string of job stints in neuroscience research, management consulting and teaching spawned a desire to stick with one thing long enough to become an expert in it. "I decided to be persevering," she says. Although she had always been interested in education and achievement, her passion for exploring grit fully emerged only after she had been pursuing it for a while.

For others, persistence may grow from a desire to test one's limits, to see how far one can go—sometimes literally. Think of endurance athletes, for whom challenge isn't merely an obstacle to accomplishing something but often the spur to action in the first place. Duckworth points to athletes who spend months or years training for a marathon not because they love the act of running long distances but because they want the personal satisfaction or public glory of having run a marathon.

Lance Armstrong entered his first distance running race at the age of 10, because he was determined to find something at which he could succeed. He won, and within three years he was winning swim meets and triathlons too—anything that tested his mettle. "If it was a suffer-fest, I was good at it," he wrote in his autobiography It's Not About the Bike.

No less remarkable in his perseverance is Chinh Chu, who has engineered some of the largest private equity deals in history. During the 1980s, Chu worked his way through college by selling books door to door, becoming his company's top salesman in a job where 60 percent of sales come after the customer has said "no" and a third come after three "no's."

In his final year of college, Chu used his persistence to land a job on Wall Street, getting his foot in the door by driving eight hours through a snowstorm in order to crash a cocktail reception hosted by Salomon Brothers. As Chu and his friend were about to be kicked out, a recruiter, impressed by their verve, offered Chu an interview. As senior managing director of the Blackstone Group, Chu has led the grueling negotiations for complex multibillion-dollar deals that literally took years to structure and complete.

Perseverance, he insists, "is purely a state of mind" that depends on one's happiness and level of discomfort. But because people are influenced by their environment, a person's grit may vary as circumstances change. Enduring the rigors of selling books door to door is a lot easier for someone hungry to prove themselves. "I don't think I'd make it if you sent me out today to sell books door to door," he offers. Diligence has not deserted him; it's just moved to a fancier address.

Also in the Mix

Passion may be the linchpin of grit, but it's not the only element. Ambition is right on its heels. For some of us, vowing to organize our closet next weekend may represent the height of our ambition. Truly gritty people, however, tend to set especially challenging long-term goals; one of Duckworth's students confidently stated that he planned to become a U.S. Senator.

Self-discipline is probably also an important part of grit, and studies have shown that gritty people tend to be highly self-disciplined. But whereas perseverance implies the ability to keep doing something, self-discipline primarily implies the ability to refrain from doing something—to stop drinking, goofing off or straying from one's diet. It doesn't embrace the ambition and zest needed to tackle a challenging goal. "Self-discipline is probably necessary for grit," Duckworth says, "but it's not sufficient."

Then there's optimism, a trait that Dean Keith Simonton of the University of California at Davis finds is extremely common among high achievers. "It helps them hang in there in times when they have to overcome all of these obstacles," he observes. "They just really believe in the end that they're going to win, and until they do, they're just going to keep on pushing, keep on making the phone calls, writing the letters, whatever they have to do."

It's this optimism, most likely, that helped Chester Carlson convince someone that the technology he had invented was worthwhile, even after more than 20 companies and the National Inventors Council rejected his work. Carlson called his new process electrophotography; today it's known as photocopying.

Grit at Home

Grit gets right into bed with you, and that may be one of the secrets of successful marriages. During the 1950s, demographer Paul Glick found that high school dropouts were more likely than graduates to be divorced, leading to speculation that people who give up on some hard things, like finishing school, are also unlikely to persevere in other matters, such as marriage.

Although plausible explanations have been proposed for the Glick Effect, the issue remains unresolved. The Penn researchers have not yet examined whether marital status or marital duration is associated with grit, although Duckworth confides they've got something in the works. It seems reasonable that people who are highly persistent in their work would also be adept at overcoming obstacles in their marriage, but it's possible that some highly driven, gritty individuals might be so focused on their career that personal relationships actually suffer.

Grit, most likely, can be taught, or at least encouraged. But one impediment to growing grit may be—surprisingly—the seemingly innocent act of parents praising a child's intelligence. In one fascinating series of studies, Stanford University psychologist Carol Dweck and her colleagues showed that children who were praised for their intelligence cared more about their grades than about learning during subsequent tasks. And after experiencing a failure, these children were less persistent than their peers who had been praised for their effort. "When you praise kids' intelligence and then they fail, they think they're not smart anymore, and they lose interest in their work," Dweck explains. "In contrast, kids praised for effort show no impairment and often are energized in the face of difficulty."

In another study, seventh graders were categorized according to whether they felt that intelligence is fixed or malleable. Students who viewed intelligence as something that can be cultivated earned progressively higher grades during the next two years, whereas those who had a fixed view of intelligence did not improve. "When you have a malleable view of intelligence, you believe in learning and you believe in effort," Dweck says. "When you have the fixed view, you don't."

Based on these findings, Dweck and colleagues designed a program (the Brainology Workshop) that explains to kids that learning creates new neuronal connections in the brain and that they themselves can foster this process. When seventh graders whose grades had been declining took the workshop, their marks shot right back up. Among a control group that received only the study skills, grades continued to fall. The program is currently being tested in New York City schools.

The data demonstrate the need for parents and teachers to praise effort rather than ability. But it also explains why so many prodigies fail to flourish as adults: The adoration showered upon them in childhood rests on their remarkable abilities rather than on their hard work.

The need for grit is generally hidden from the young until they head off to college or enter the workforce. That's when it first becomes necessary to chart one's own course and set one's own goals. Before then, achievement hinges largely on doing your homework—and that's chosen by others and assigned to you. Nonetheless, says Duckworth, perseverance clearly matters for kids. Gritty youngsters get better grades than their peers. And, as a study of participants in the National Spelling Bee revealed, kids who ranked high in grit were more likely to reach the final round of the competition, for the simple reason that they had worked harder than their rivals to prepare for the event.

Global Grit

Some argue that grit is engrained in the American psyche. In his book The Hypomanic Edge, Johns Hopkins psychiatrist John Gartner observes that the U.S. and other countries founded by immigrants tend to have high rates of people with mild mania. These folks tend to be energetic risk takers—precisely the type of person likely to undertake a bold endeavor like immigration. Moreover, such people "are able to persist when others might get depressed," notes U.C. Davis psychologist Dean Keith Simonton.

Today the Pacific Rim countries may best exemplify grit. Think of Japan's astounding rebirth following its defeat in World War II, transforming itself from a near-feudal empire to a modernized republic and economic powerhouse. Or the long hours and Spartan conditions that welcome laborers in China's many factories. The writings of Confucius teach that people can reach perfection through practice and effort. Many Chinese folktales focus on feats of persistence—for example, a boy who grew up in such poverty that he couldn't afford oil for his lamp but who nonetheless worked very hard and succeeded in becoming a government official.

Parental expectations are uniformly high in Asian cultures: Even though children in Japan outperform American children on most educational measures, their parents tend to say, "My kids can do better." By contrast, a large proportion of American parents report that they are satisfied with their kids' academic performance, lackluster though it may be by international standards.

Of course, hard work isn't the same as grit, and perseverance in response to parental obligations or social norms doesn't come close to suggesting the lit-from-within passion that drives most innovators. But external motivators like family expectations and internal motivators like passion often work together, in symbiosis. "It's possible," says Duckworth, "to do something because your parents say you should do it but then gradually learn to love it."

When giftedness expert Ellen Winner of Boston College visited China in the late 1980s, she was "absolutely astonished" by an after-school program in which first graders were required to choose an art form such as calligraphy or traditional ink and brush drawing—and they were to continue practicing it for six years. "I asked a teacher, 'What happens if a child changes his mind or says that he didn't choose the right thing?' She looked at me like I was crazy and said, 'That never happens.'"

At first Winner was horrified that children were expected to stick with something that had been thrust upon them at such an early age: "It was like an arranged marriage. But then I thought, 'There's something really great about this, because these kids are really gaining mastery. And when they see that they're becoming good, they develop motivation.'"

In a global marketplace where innovation is more critical to viability than ever before, there's an urgency to identifying and, eventually, cultivating, the elements of success. Duckworth, Dweck and a host of others are demonstrating that grit is an important contributor.

Another thing they know: This isn't your grandmother's view of grit. The quality Duckworth finds so intriguing has little to do with clenched teeth. Rather, it's a force of motivation so luminous that, as mathematician Andrew Wiles found, it constantly renews itself.

Despite instant messaging, speed dating and immediate gratification, the idea that perseverance pays off big-time is slowly gathering steam. It augurs a far more democratic vision than a culture of achievement that recognizes only talent. No wonder grit is on its way to becoming The Next Big Thing.